The hubcaps on the Impala disappear and reappear several times while this car is being used.
As they are driving the Dodge Charger, the windshield changes from cracked to intact between shots.
The blue Chevy Impala has something hanging from the underside of the car. It disappears between shots and then returns later on.
The license plate on the blue Chevy changes (it's RTG911). In one scene where the car is driving up a hill, it's different.
The Dodge Charger they are driving is a 1969 model, yet when the Charger and the one police car are sideswiping each other and he ends up running the police car off a bridge into a river, a 1968 model is shown.
The radio used to listen to the cops, is in fact, a Realistic TRC-46 CB (Citizens Band) radio from Radio Shack. This type of radio cannot pick up police calls and also is in Single Sideband Mode, LSB, which would make hearing VHF/UHF police band impossible, even if it could.
The first getaway car is repeatedly referred to as a 1967 or 1968 Chevy by the police. It is actually a 1966 Impala and the differences between the model years are obvious.
When Larry executes the sharp turn in front of the bus, there are preexisting tire tracks on the roadway shoulder from previous takes or practice runs.
After the green Charger sideswipes and runs one of the police cars off the road, a subsequent scene shows no damage to the right side of the Charger that veered into the police vehicle.
When Deke is replacing a tire on the yellow Dodge Charger, the reflection of the camera crew can clearly be seen in the driver's-side door.
In almost all close-up shots of an actor wearing (sun)glasses, the crew and/or camera rigs are visible in the reflections. For example, when the trio are driving away from the supermarket robbery, two studio lights are clearly reflected in Larry's glasses.
As Larry, Mary and Deke go into the bar to shoot some pool, a boom mic is seen to be following them along under the trees as they walk behind the Charger.
As the grocery store manager and his female assistant talk over the dire situation involving the manager's family you can see the reflection of a hand and partial boom mic pole in the huge glass window adorning the upstairs office.
When they are waiting out the roadblock, and going into the tavern, you can quite visibly see the boom mic off to the left side of the picture. It's visible for the entire scene, probably a good 15 seconds, and it just keeps following the actors.